There is still a risk of snow, as this crocus last year shows all too well, yet the garden is coming to life again. If your soil is not water-logged (or frozen), new flower beds can be prepared, cool season plantings can be done (for example, bare root roses, pansies, primroses and so on). While some people advise sowing hardy seeds such a field poppy in February, there is still a danger of heavy rain and frosts to damage new sprouting seeds. A later sowing is the way I tend to go now to avoid the seeds being washed away, if not already sowed in the autumn. Once rooted, the seedlings can anchor themselves.
When it comes to pruning shrub roses, they should be done from late February through to the end of March (before they go into full growth). General shrub pruning should be done soon too, so long as there is not a deep freeze (we take our chances here with the more tender shrubs). Those hardy vegetable gardeners will also likely be busy preparing their new beds with soil amendments etc., ready for early plantings. Major tree limb pruning should in many cases be done during winter dormancy (Walnut in particular will bleed copious amounts of sap due to the rising sap pressure in Spring).
Keep in mind that sometime around this time of year there are other garden tasks that one can carry out, depending on your particular gardening philosophy (across the spectrum of minimal intervention through to micro-management). Apart from a general tidy-up of edging the lawn, shrub pruning, some raking, and maybe a quick lawn trim if required, brushing of slippery walkways would be good. If you want to use surface cleaners, there are various products out there, but try to use something plant-friendly and not acidic, so basically a surfactant/detergent that can be brushed on and rinsed off, and is biodegradable. Many of the moss killers can stain concrete (they often contain iron), and check on their toxicity to your garden if you really want to use them. It would be wise to scrape drainage channels to improve drying where the algae/lichen/moss are growing.
Probably one of the best things you can do if you like your lawn and the soil is acidic, is to apply dolomitic lime or similar: the lime helps condition the soil and increases nutrient availability, while discourage too much moss. It should not be applied in excess under rhodos or azaleas etc. that need acidic conditions.
For your fruit trees, if dormant oil application is required, it really needs a clear fine day with no wind, rain or frost. Good luck with that one.